الفهرس 
List of TablesOnly 14 pages are availabe for public view
 |  | from | 148 |  |  |
| | | from | 148 | | |
Abstract
The study was conducted at Microbiology, Mycology and Immunology Department, Faculty of Veterinary Medicine, University of Sadat city. This study aimed to investigate the effect of some feed additives as probiotics and prebiotics on the growth performance and immune response in broiler chickens.
A total of 150 one day old commercial broiler chicks (Cobb500) obtained from local hatchery (MiserAl-Arabia Company), the chicks were first weighted and randomly assigned into six experimental groups (25 each).The 1stgroup is the control group received no vaccine and no challenge. The 2ndgroup is the control group challenged with E. coli O78 (1x108 CFU/ml) at day 28 with no vaccine. The 3rdgroup received MORI-Max (UniTrade, Egypt) commercial probiotics (composed of Bacillus subtilis MORI91, Clostridium butyricumM7, Lactobacillus plantarumK34 Functional organic acid, Soluble β–glucan, Nucleotides and 1 Deoxynojirimycin) at dose of 1 gm. /kg feed and vaccinated with poul-vac E.coli vaccine (Pfizer, USA) at day 14 and challenged with E. coli O78 (1x108 CFU/ml) at day 28. The 4thgroup received only MORI-Max commercial probiotics mixture at dose of 1 gm. /kg feed and challenged with E. coli O78 (1x108 CFU/ml) at day 28. The 5thgroup received Yikangsu (Oligosaccharide) commercial prebiotic (Jiangsu China, China) at a dose of 0.5 gm./ kg feed and vaccinated with poul-vac E.coli vaccine (Pfizer, USA) at day 14 and challenged with E. coli O78 (1x108 CFU/ml) at day 28. The 6thgroup received Yikangsu (Oligosaccharide) commercial prebiotic at a dose of 0.5 gm./ kg feed and challenged with E. coli O78 (1x108 CFU/ml) at day 28.
The experiment was continued for five weeks (35 days), during which all groups were observed daily and clinical signs were recorded, performance parameters and mortality rate of birds were estimated weekly and collection of samples from birds of each group wasperformed. the collected Samples included blood which collected from wing vein weekly for serological examination for evaluation of immunity, cloacal samples from birds weretaken weekly for bacteriological examination. Thefollowing results were observed when comparing treated groups with control groups and summarized as follow:
7-1-Effect of probiotics and prebiotic on body weight:
The groups obtained probiotics and prebiotics achieved a higher weekly body weight compared with the control groups, where during the 1st, 4thand 5thweeks, the weekly body weight development in groups 3 and 4 was significantly (P<0.05)higher body weight compared with the control groups (1 and 2).
7-2-Effect of vaccine, probiotic and prebiotic on body gain (gm.):
The increased body weight led to increased body weight gain where during the 1stand 3rdweeks, groups have probiotic (3-4) achieved significantly (P<0.05) a higher weekly body gain (gm.) compared with the control groups (1 and 2) and the groups obtained prebiotics5Interestingly, in the 4thweek, there is a significant (P<0.05) increase in the weekly body gain in groups 3, 4, 5 in contrast with other groups. By the end of the 5thweeks, broiler chickens obtained probiotics especially group (4) achieved a significant (P<0.05).higher weekly body gain compared with other groups
7-3-Effect of vaccine, probiotic and prebiotic on relative growth rate:
During the 1st week supplementation of broiler chickens with probiotics and prebiotics (groups 3, 4, 5, and 6) increased significantly (P<0.05), the relative growth rate (%) compared with the control groups 1-2 during the 4thand 5thweeks, broiler chickens received probiotics mainly group (4) achieved significantly (P<0.05) higher weekly relative growth rate (%) compared with control groups.